Log Message:
Update to go-protobuf version 1.3.2.

Pkgsrc changes:
 * Update PLIST

Upstream notable changes:
* #785: grpc code generation: add an UnimplementedServer type
  implementing each server interface, returning an unimplemented
  error for each method
* #851: convert prints to `os.Stderr` to use `log.Printf`
* #883: jsonpb: fix marshaling of Duration with negative nanoseconds